ub_ctx_hosts
if((retval=ub_ctx_hosts(ctx, buf)) !=0 ) {
retval=ub_ctx_hosts(ctx, buf);
int ub_ctx_hosts(struct ub_ctx* ctx, const char* fname);
if((retval=ub_ctx_hosts(ctx, buf)) !=0 ) {
retval=ub_ctx_hosts(ctx, buf);
int ub_ctx_hosts(struct ub_ctx* ctx, const char* fname);
r = ub_ctx_hosts(ctx, optarg);